1. Field of the Invention
Embodiments of the invention are related to semiconductor devices having integrated circuits on a chip.
2. Related Art
In Japanese Unexamined Patent Application Publication No. H5-175427 (“Document 1”), some resistors are inserted into each of power source lines of a plurality of circuit blocks in order to prevent surge voltage in excess of stationary state. In addition, in Japanese Unexamined Patent Application Publication No. 2010-288444 (“Patent Document 2”) (see FIG. 6), a low-pass filter is constituted by a capacitor arranged in parallel with semiconductor integrated circuits and a resistor arranged in power source side thereof in order to compensate power source voltage for instantaneous drop of power source voltage in particular.
However, a configuration such as that shown in Patent Document 1 is not well suited for dealing with instantaneous drops of power source voltage. Additionally, when a plurality of functional circuits are connected to a common power source in parallel, to form a structure such as that shown in Patent Document 2, the sum of electric current through the plurality of functional circuits flows to a resistor forming a low-pass filter. Therefore, with such a configuration, voltage drop of this resistor needs to be taken into consideration. That is, in order that direct input voltage to functional circuits thereof as a power supply becomes voltage value or greater required to operate, by reducing resistance value of the resistor forming the low-pass filter, it is required that voltage drop thereby is forced to become predetermined voltage or less to be set. Then, filter function may not be sufficiently performed for compensating instantaneous drop of power source voltage because resistance value of the resistor is small. Further, when attaching externally capacitors arranged in parallel with semiconductor integrated circuit and resistors arranged in power source side thereof, space and cost for terminals and external components of semiconductor integrated circuit increase, and a device scale using the semiconductor integrated circuit consequently becomes larger. Thus, as described above, there exists certain problems in the related art.